TWI513810B - Imaging device module - Google Patents

Description

Camera parts

The present invention relates to an image pickup component, and more particularly to an image pickup component equipped on an image pickup apparatus.

In recent years, in an imaging device such as a digital camera, a plurality of CCD (Charge Coupled Device) image sensors and CMOS (Complementary Metal Oxide Semiconductor, Complementary Metal Oxide Semiconductor) are used depending on the number of pixels of the imaging device. Image sensor such as image sensor.

When such imaging elements are exposed to high temperatures, problems such as noise generation may occur.

Therefore, the industry is investigating that a heat radiation member is provided on the image pickup element to suppress an increase in temperature of the image pickup element.

More specifically, for example, in the solid-state imaging device, a heat conduction member including a graphite sheet is provided on the back surface of the imaging surface of the imaging element, and is in contact with the imaging surface of the imaging element so as to be in contact with the graphite sheet. An electronic cooling element such as a Peltier element and a heat releasing member are provided on the side surface (for example, refer to Japanese Laid-Open Patent Publication No. 2008-177917).

In the solid-state imaging device described in Japanese Laid-Open Patent Publication No. 2008-177917, the electronic cooling element and the heat radiation member are disposed on the side surface side of the image sensor, and the heat conduction efficiency is arranged in the thickness direction so as to contact the electronic cooling element and the image sensor. The higher graphite sheet serves as a heat conduction member, thereby achieving an improvement in heat dissipation and miniaturization of the solid-state imaging device.

However, since the graphite sheet used in Japanese Laid-Open Patent Publication No. 2008-177917 has a high price, it is inferior in terms of cost.

Further, since the image sensor has a change in sensitivity depending on temperature conditions, it is required to reduce temperature unevenness (to achieve uniformity of temperature) in order to achieve uniformity of sensitivity.

Therefore, an object of the present invention is to provide an image pickup unit which can achieve cost reduction, uniform temperature, and excellent heat dissipation.

An imaging device according to the present invention includes an imaging element including a light incident surface on which light is incident and a back surface disposed on a side opposite to the light incident surface, and a thermally conductive sheet provided on the back surface for enabling The heat radiation from the image pickup element is released; and the heat conductive sheet contains plate-shaped boron nitride particles, and the thermal conductivity of the thermally conductive sheet in a direction orthogonal to the thickness direction is 4 W/m·K or more.

In the image pickup device, the heat conductive sheet is provided on the back surface of the image pickup element disposed on the opposite side of the light incident surface, and specifically includes a plate-like boron nitride particle and a direction orthogonal to the thickness direction ( That is, the thermal conductivity sheet having a thermal conductivity of 4 W/m‧K or more in the plane direction). Therefore, the heat can be uniformly diffused in the plane direction, the temperature unevenness can be reduced (the temperature is uniformized), and the excellent heat release property can be ensured, and as a result, the sensitivity can be improved.

Further, since such a thermally conductive sheet can be manufactured at a lower cost than the graphite sheet, cost reduction can be achieved.

Further, the image pickup unit of the present invention is preferably a CMOS image sensor.

Further, the image pickup unit of the present invention is preferably a back side illumination type CMOS image sensor.

According to the image pickup component of the present invention, uniformity of temperature can be achieved, and excellent heat dissipation can be ensured, and cost reduction can be achieved.

1 is a schematic configuration diagram of an embodiment of an image pickup component of the present invention, and FIG. 2 is a step diagram for explaining a method of manufacturing the heat conductive sheet included in the image pickup component shown in FIG. 1. FIG. A perspective view of a thermally conductive sheet as shown.

In FIG. 1, the imaging element 1 includes an imaging element 2 and a thermally conductive sheet 3 for discharging heat generated from the imaging element 2.

The imaging element 2 is an element including a photoelectric conversion element (a light-receiving element 10 to be described later) that converts received light into an electric signal, and is provided in a plurality of imaging devices (not shown) such as a digital camera or a digital camera, depending on the number of pixels. .

Examples of the image pickup device 2 include a CCD image sensor, a surface illumination type CMOS image sensor, and a CMOS image sensor such as a back side illumination type CMOS image sensor. In the present embodiment, the image pickup element 2 is used. The CMOS image sensor is used in detail, and the surface illumination type CMOS image sensor is used in detail.

Such an imaging element 2 includes a collecting lens 4, a filter 5, a circuit board 6, and a light receiving substrate 7.

The condensing lens 4 is a lens which is formed in a substantially semi-elliptical shape in cross section, and has a bottom surface which is in close contact with the filter 5 and an upper surface (curved surface) which is exposed as a light incident surface into which light is incident.

The condensing lens 4 is provided in the imaging element 2 in a plurality (three) so as to correspond to the green filter 5G, the red filter 5R, and the blue filter 5B which will be described later.

The filter 5 is formed as a thin film, and includes a green filter 5G, a red filter 5R, and a blue filter 5B.

The green filter 5G is a light-transmissive film having a higher transmittance of light in the green band, and splits the light incident from the light incident surface of the condensing lens 4 to pass the green light.

The red filter 5R is a light-transmissive film having a higher transmittance of light in a red band, and splits light incident from the light incident surface of the condensing lens 4 to pass the red light.

The blue filter 5B is a light-transmissive film having a higher transmittance of light in the blue band, and splits light incident from the light incident surface of the condensing lens 4 to pass the blue light.

The green filter 5G, the red filter 5R, and the blue filter 5B are manufactured by a known method, and the filter 5 is formed by being arranged adjacent to each other.

The circuit board 6 includes an insulating layer 8 and a conductor pattern 9 embedded in the insulating layer 8.

The insulating layer 8 is formed of a light transmissive material that transmits light, and is inserted between the conductor patterns 9 in order to insulate the conductor pattern 9.

The light-transmitting material is not particularly limited, and examples thereof include cerium oxide and the like, and further, cerium oxide added thereto by adding, for example, phosphorus or boron to the cerium oxide.

The conductor pattern 9 is formed of, for example, a metal material such as aluminum or copper, and is formed, for example, in a specific pattern by a known printing method and embedded in the insulating layer 8.

Such a conductor pattern 9 is electrically connected to an external member by transmitting an electric signal obtained by the light receiving element 10 (described later).

The light-receiving substrate 7 is, for example, a substrate including a polysilicon oxide resin, and is provided so as to contact the circuit board 6.

Further, the light receiving substrate 7 includes the light receiving element 10.

The light-receiving element 10 is a photoelectric conversion element that converts the received light into an electric signal, and is roughly rectangular in cross section.

The light-receiving element 10 is provided in a plurality (three) corresponding to the optical filter 5, and each of the light-receiving elements 10 is opposed to each of the filters 5 (green filter 5G, red filter 5R, and The blue filter 5B) is embedded in the light-receiving substrate 7.

Further, each of the light receiving elements 10 is disposed such that one side thereof is exposed from the light receiving substrate 7 and is connected to each of the color filters 5 (the green filter 5G, the red filter 5R, and the blue filter 5B). The other side opposite to the one side (the surface on the side in contact with the circuit board 6) faces each other.

Further, the light-receiving substrate 7 is provided on the back surface disposed on the opposite side of the light incident surface, and serves as the other side surface facing the light incident surface side of the condensing lens 4 (the surface contacting the light-receiving substrate 7 and the circuit board 6). The back surface of the light-receiving substrate 7 (the back surface of the image sensor 2) is formed into a flat surface, and the heat conductive sheet 3 is provided on the back surface.

The thermally conductive sheet 3 is formed in a flat shape, and is disposed such that its surface is in close contact with the back surface of the light receiving substrate 7 (the back surface of the image sensor 2).

Such a thermally conductive sheet 3 contains boron nitride particles.

Specifically, the thermally conductive sheet 3 contains boron nitride (BN) particles as an essential component, and further contains, for example, a resin component.

The boron nitride particles are formed into a plate shape (or a scaly shape), and are dispersed in the thermally conductive sheet 3 in a form oriented in a specific direction (described later).

The length in the longitudinal direction of the boron nitride particles (the maximum length in the direction orthogonal to the thickness direction of the sheet) is, for example, 1 to 100 μm, preferably 3 to 90 μm. Further, the length of the boron nitride particles in the longitudinal direction is 5 μm or more on average, preferably 10 μm or more, more preferably 20 μm or more, particularly preferably 30 μm or more, and most preferably 40 μm or more, and is usually, for example, 100. Below μm, preferably less than 90 μm.

Further, the thickness of the boron nitride particles (the length in the thickness direction of the sheet, that is, the length in the short-side direction of the particles) is, for example, 0.01 to 20 μm, preferably 0.1 to 15 μm.

Further, the aspect ratio (length in the longitudinal direction/thickness) of the boron nitride particles is, for example, 2 to 10,000, preferably 10 to 5,000.

Further, the average particle diameter of the boron nitride particles measured by a light scattering method is, for example, 5 μm or more, preferably 10 μm or more, more preferably 20 μm or more, particularly preferably 30 μm or more, and most preferably 40 μm. The above is usually 100 μm or less.

Further, the average particle diameter measured by the light scattering method is a volume average particle diameter measured by a dynamic light scattering type particle size distribution measuring apparatus.

When the average particle diameter of the boron nitride particles measured by the light scattering method is less than the above range, the thermally conductive sheet 3 becomes brittle and the workability is lowered.

Further, the bulk density (JIS K 5101, apparent density) of the boron nitride particles is, for example, 0.3 to 1.5 g/cm ³ , preferably 0.5 to 1.0 g/cm ³ .

Further, as the boron nitride particles, commercially available products or processed products obtained by processing them can be used. For example, the "PT" series (for example, "PT-110") manufactured by Momentive Performance Materials Japan Co., Ltd. and the "SHOBN UHP" series manufactured by Showa Denko Co., Ltd. (for example, " SHOBN UHP-1", etc.).

The resin component is a dispersion medium (matrix) in which boron nitride particles are dispersed, and examples thereof include a resin component such as a thermosetting resin component and a thermoplastic resin component.

Examples of the thermosetting resin component include an epoxy resin, a thermosetting polyimide, a phenol resin, a urea resin, a melamine resin, an unsaturated polyester resin, a diallyl phthalate resin, and a poly A silicone resin, a thermosetting amine resin, or the like.

Examples of the thermoplastic resin component include polyolefin (for example, polyethylene, polypropylene, ethylene-propylene copolymer, etc.), acrylic resin (for example, polymethyl methacrylate, etc.), polyvinyl acetate, and ethylene. Vinyl acetate copolymer, polyvinyl chloride, polystyrene, polyacrylonitrile, polyamine, polycarbonate, polyacetal, polyethylene terephthalate, polyphenylene ether, polyphenylene sulfide, polyfluorene , polyether oxime, polyether ether ketone, polyallyl fluorene, thermoplastic polyimide, thermoplastic amine ester resin, polyamine bismaleimide, polyamidimide, polyetherimine, Bismaleimide III Resin, polymethylpentene, fluorinated resin, liquid crystal polymer, olefin-vinyl alcohol copolymer, ionic polymer, polyarylate, acrylonitrile-ethylene-styrene copolymer, acrylonitrile-butadiene-styrene Copolymer, acrylonitrile-styrene copolymer, and the like.

These resin components may be used alone or in combination of two or more.

Among the resin components, an epoxy resin is preferred.

The epoxy resin is in any form of liquid, semi-solid or solid at normal temperature.

Specifically, examples of the epoxy resin include bisphenol type epoxy resins (for example, bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, hydrogenated bisphenol) A type epoxy resin, dimer acid modified bisphenol type epoxy resin, etc.), novolak type epoxy resin (for example, phenol novolak type epoxy resin, cresol novolak type epoxy resin, biphenyl type ring) Oxygen resin, etc., naphthalene type epoxy resin, fluorene type epoxy resin (for example, bisaryl fluorene type epoxy resin, etc.), triphenylmethane type epoxy resin (for example, trishydroxyphenylmethane type epoxy resin) Or an aromatic epoxy resin; for example, a nitrogen-containing epoxy resin such as triglycidyl isocyanurate (triglycidyl isocyanurate) or an ethyl carbendazole epoxy resin; for example, fat A family epoxy resin; for example, an alicyclic epoxy resin (for example, a bicyclic ring type epoxy resin); for example, a glycidyl ether type epoxy resin; for example, a glycidylamine type epoxy resin or the like.

These epoxy resins may be used alone or in combination of two or more.

Preferably, a combination of a liquid epoxy resin and a solid epoxy resin is used, and a combination of a liquid aromatic epoxy resin and a solid aromatic epoxy resin is preferably used. Specific examples of such a combination include a combination of a liquid bisphenol type epoxy resin and a solid triphenylmethane type epoxy resin, or a liquid bisphenol type epoxy resin and a solid form. A combination of bisphenol type epoxy resins.

Further, as the epoxy resin, a semi-solid epoxy resin is preferably used, and a semi-solid aromatic epoxy resin is preferably used alone. More specifically, such an epoxy resin is a semi-solid fluorene type epoxy resin.

When it is a combination of a liquid epoxy resin and a solid epoxy resin, or a semi-solid epoxy resin, the step followability (described later) of the thermally conductive sheet 3 can be improved.

Further, the epoxy equivalent of the epoxy resin is, for example, 100 to 1000 g/eqiv., preferably 160 to 700 g/eqiv., and the softening temperature (ring and ball method) is, for example, 80 ° C or lower (specifically, 20 to 80 ° C). It is preferably 70 ° C or less (specifically, 25 to 70 ° C).

Further, the epoxy resin has a melt viscosity at 80 ° C of, for example, 10 to 20,000 mPa ‧ s, preferably 50 to 15,000 mPa ‧ s. When two or more types of epoxy resins are used in combination, the melt viscosity of the mixtures is set within the above range.

Further, when an epoxy resin which is solid at normal temperature and an epoxy resin which is liquid at normal temperature are used in combination, the softening temperature is, for example, a first epoxy resin which is less than 45 ° C, preferably 35 ° C or less. The second epoxy resin having a softening temperature of, for example, 45 ° C or higher, preferably 55 ° C or higher is used in combination. Thereby, the dynamic viscosity of the resin component (mixture) (described later in accordance with JIS K 7233) can be set within a desired range, and the step followability of the thermally conductive sheet 3 can be improved.

Further, an epoxy resin composition can be prepared by including, for example, a curing agent and a curing accelerator in the epoxy resin.

The hardener is a latent hardener (epoxy resin hardener) which hardens an epoxy resin by heating, and examples thereof include an imidazole compound, an amine compound, an acid anhydride compound, a guanamine compound, an anthraquinone compound, and an imidazoline compound. Wait. Further, in addition to the above, a phenol compound, a urea compound, a polysulfide compound, and the like may be mentioned.

Examples of the imidazole compound include 2-phenylimidazole, 2-methylimidazole, 2-ethyl-4-methylimidazole, and 2-phenyl-4-methyl-5-hydroxymethylimidazole.

The amine compound may, for example, be an aliphatic polyamine such as ethylenediamine, propylenediamine, diethylenetriamine or triethylenetetramine, such as m-phenylenediamine, diaminodiphenylmethane or diamine. An aromatic polyamine such as a diphenyl hydrazine.

Examples of the acid anhydride compound include phthalic anhydride, maleic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, and 4-methyl-hexahydrophthalic anhydride. Methylic acid anhydride, pyromellitic anhydride, dodecenyl succinic anhydride, dichlorosuccinic anhydride, benzophenone tetracarboxylic anhydride, chlorinic anhydride, and the like.

Examples of the guanamine compound include dicyanodiamine, polyamine, and the like.

Examples of the ruthenium compound include diammonium adipate and the like.

Examples of the imidazoline compound include methyl imidazoline, 2-ethyl-4-methylimidazoline, ethyl imidazoline, isopropyl imidazoline, 2,4-dimethylimidazoline, and phenyl. Imidazoline, undecyl imidazoline, heptadecyl imidazoline, 2-phenyl-4-methylimidazoline and the like.

These hardeners may be used alone or in combination of two or more.

As the curing agent, an imidazole compound is preferred.

The hardening accelerator may, for example, be a tertiary amine compound such as triethylenediamine or tris-2,4,6-dimethylaminomethylphenol, such as triphenylphosphine or tetraphenylphosphonium tetraphenyl. A phosphorus compound such as a borate or a tetra-n-butylphosphonium-o,o-diethyldithiophosphate, such as a quaternary ammonium salt compound, an organometallic salt compound, and the like. These hardening accelerators may be used alone or in combination of two or more.

The compounding ratio of the curing agent in the epoxy resin composition is, for example, 0.5 to 50 parts by mass, preferably 1 to 10 parts by mass, based on 100 parts by mass of the epoxy resin, and the ratio of the curing accelerator is, for example, 0.1 to 10 parts by mass. It is preferably 0.2 to 5 parts by mass.

The curing agent and/or the curing accelerator may be prepared by using a solvent solution and/or a solvent dispersion which is dissolved and/or dispersed by a solvent, if necessary.

Examples of the solvent include ketones such as acetone and methyl ethyl ketone, and esters such as ethyl acetate, and organic solvents such as guanamine such as N,N-dimethylformamide. Further, examples of the solvent include water, for example, an aqueous solvent such as an alcohol such as methanol, ethanol, propanol or isopropanol. The solvent is preferably an organic solvent, and more preferably a ketone or a guanamine.

Among the thermoplastic resin components, polyolefin is preferred.

As the polyolefin, a polyethylene or an ethylene-propylene copolymer is preferred.

Examples of the polyethylene include low density polyethylene and high density polyethylene.

Examples of the ethylene-propylene copolymer include a random copolymer of ethylene and propylene, a block copolymer, and a graft copolymer.

These polyolefins may be used alone or in combination of two or more.

Further, the weight average molecular weight and/or the number average molecular weight of the polyolefin is, for example, 1,000 to 10,000.

Further, the polyolefin may be used singly or in combination of plural kinds.

Further, the resin component was subjected to a dynamic viscosity test in accordance with JIS K 7233 (bubble viscosity meter method) (temperature: 25 ° C ± 0.5 ° C, solvent: butyl carbitol, resin component (solid content) concentration: 40% by mass) The measured dynamic viscosity is, for example, 0.22 × 10 ^-4 to 2.00 × 10 ^-4 m ² /s, preferably 0.3 × 10 ^-4 to 1.9 × 10 ^-4 m ² /s, and more preferably 0.4 × 10 ^{- 4} ~ 1.8 × 10 ^-4 m ² / s. Further, the dynamic viscosity may be set to, for example, 0.22 × 10 ^-4 to 1.00 × 10 ^-4 m ² /s, preferably 0.3 × 10 ^-4 to 0.9 × 10 ^-4 m ² /s, and more preferably 0.4 × 10 ^-4 ~ 0.8 × 10 ^-4 m ² / s.

When the dynamic viscosity of the resin component exceeds the above range, the thermal conductive sheet 3 may not be provided with excellent flexibility and step followability (described later). On the other hand, when the dynamic viscosity of the resin component is less than the above range, the boron nitride particles may not be aligned in a specific direction.

Furthermore, in the dynamic viscosity test according to JIS K 7233 (bubble viscometer method), the rising speed of the bubble in the resin component sample is compared with the rising speed of the bubble in the standard sample (known dynamic viscosity), and the rise is judged. The dynamic viscosity of the standard sample with the same speed is the dynamic viscosity of the resin component, thereby determining the dynamic viscosity of the resin component.

Further, in the thermally conductive sheet 3, the volume ratio of the boron nitride particles (the solid content component, that is, the volume fraction of the boron nitride particles to the total volume of the resin component and the boron nitride particles) is, for example, 35 volumes. % or more is preferably 60% by volume or more, preferably 65% by volume or more, and usually, for example, 95% by volume or less, preferably 90% by volume or less.

When the content ratio of the volume basis of the boron nitride particles is less than the above range, the boron nitride particles may not be aligned in the specific direction in the thermally conductive sheet 3. On the other hand, when the content ratio of the volume basis of the boron nitride particles exceeds the above range, the thermally conductive sheet 3 may become brittle and workability may deteriorate.

In addition, the blending ratio of the boron nitride particles to the mass basis (the total amount of the solid content component) of 100 parts by mass of each component (the boron nitride particles and the resin component) forming the thermally conductive sheet 3 is, for example, 40 to 95. The mass fraction is preferably 65 to 90 parts by mass, and the blending ratio of the resin component to the mass basis of 100 parts by mass of the total amount of each component forming the thermally conductive sheet 3 is, for example, 5 to 60 parts by mass, preferably 10 to 10 parts by mass. 35 parts by mass. Further, the blending ratio of the boron nitride particles to 100 parts by mass of the resin component is, for example, 60 to 1900 parts by mass, preferably 185 to 900 parts by mass.

In the case where two types of epoxy resins (the first epoxy resin and the second epoxy resin) are used in combination, the mass ratio of the first epoxy resin to the second epoxy resin (the mass of the first epoxy resin / The mass of the second epoxy resin can be appropriately set according to the softening temperature of each epoxy resin (the first epoxy resin and the second epoxy resin), and is, for example, 1/99 to 99/1, preferably 10/. 90~90/10.

Further, the resin component may contain, for example, a polymer precursor (for example, a low molecular weight polymer containing an oligomer) and/or a monomer in addition to the above components (polymer).

Next, a method of forming the thermally conductive sheet 3 will be described.

In this method, the above components are first formulated in the above-mentioned blending ratio, and stirred and mixed, whereby a mixture is prepared.

In the stirring and mixing, the components are mixed with high efficiency. For example, the solvent may be blended together with the above components, or the resin component (preferably a thermoplastic resin component) may be melted by heating, for example.

The solvent is the same as the above-mentioned organic solvent. Further, when the curing agent and/or the curing accelerator are prepared as a solvent solution and/or a solvent dispersion, the solvent may be supplied as a mixed solvent for stirring and mixing without adding a solvent during stirring and mixing. Solvent for solution and / or solvent dispersion. Alternatively, a solvent may be further added as a mixed solvent at the time of stirring and mixing.

In the case of stirring and mixing using a solvent, the solvent is removed after stirring and mixing.

To remove the solvent, for example, it is allowed to stand at room temperature for 1 to 48 hours, for example, at 40 to 100 ° C for 0.5 to 3 hours, or for example, at a temperature of 20 to 60 ° C for 0.5 to 3 hours under a reduced pressure of 0.001 to 50 kPa.

When the resin component is melted by heating, the heating temperature is, for example, near or above the softening temperature of the resin component, specifically 40 to 150 ° C, preferably 70 to 140 ° C.

Next, the obtained mixture is hot pressed in this method.

Specifically, as shown in FIG. 2( a ), the mixture is hot-pressed via, for example, two release films 16 as needed, whereby the pressed sheet 3A is obtained. With respect to the conditions of hot pressing, the temperature is, for example, 50 to 150 ° C, preferably 60 to 140 ° C, and the pressure is, for example, 1 to 100 MPa, preferably 5 to 50 MPa, and the time is, for example, 0.1 to 100 minutes, preferably 1 ~30 minutes.

Further preferably, it is a vacuum hot press mixture. The degree of vacuum during vacuum hot pressing is, for example, 1 to 100 Pa, preferably 5 to 50 Pa, and the temperature, pressure and time are the same as those of the above hot pressing.

When the temperature, pressure, and/or time at the time of hot pressing are outside the above range, the void ratio P (described later) of the thermally conductive sheet 3 may not be adjusted to a desired value.

The pressed sheet 3A obtained by hot pressing has a thickness of, for example, 50 to 1000 μm, preferably 100 to 800 μm.

Next, in this method, as shown in Fig. 2(b), the pressed sheet 3A is divided into a plurality of (for example, four) sheets to obtain a divided sheet 3B (dividing step). When the pressed sheet 3A is divided, the pressed sheet 3A is cut in the thickness direction thereof so as to be divided into a plurality of pieces when projected in the thickness direction. In addition, the pressed sheet 3A is cut so that each of the divided sheets 3B has the same shape when projected in the thickness direction.

Next, in this method, as shown in FIG. 2(c), each of the divided sheets 3B is laminated in the thickness direction to obtain a laminated sheet 3C (layering step).

Thereafter, in this method, as shown in Fig. 2 (a), the laminated sheet 3C (preferably vacuum hot pressing) (hot pressing step) is formed. The conditions of hot pressing are the same as those of the above mixture.

The thickness of the laminated sheet 3C after the hot pressing is, for example, 1 mm or less, preferably 0.8 mm or less, and is usually 0.05 mm or more, preferably 0.1 mm or more.

Then, as shown in FIG. 3, in order to effectively arrange the boron nitride particles 14 in the heat conductive sheet 3 in the resin component 15 in a specific direction, the above-described dividing step (Fig. 2(b)) is repeated. A series of steps of the lamination step (Fig. 2(c)) and the hot pressing step (Fig. 2(a)). The number of repetitions is not particularly limited, and may be appropriately set depending on the filling state of the boron nitride particles, and is, for example, 1 to 10 times, preferably 2 to 7 times.

Further, in the hot pressing step (Fig. 2 (a)), for example, the mixture and the laminated sheet 3C may be rolled by a plurality of rolls or the like.

Thereby, the thermally conductive sheet 3 shown in FIGS. 2 and 3 can be formed.

The thickness of the thermally conductive sheet 3 to be formed is, for example, 1 mm or less, preferably 0.8 mm or less, and is usually 0.05 mm or more, preferably 0.1 mm or more.

Further, the volume ratio of the boron nitride particles 14 in the thermally conductive sheet 3 (the solid content component, that is, the volume fraction of the total volume of the boron nitride particles 14 to the resin component 15 and the boron nitride particles 14) is as above The content is, for example, 35% by volume or more (preferably 60% by volume or more, more preferably 75% by volume or more), and usually 95% by volume or less (preferably 90% by volume or less).

When the content ratio of the boron nitride particles 14 is less than the above range, the boron nitride particles 14 may not be aligned in a specific direction in the thermally conductive sheet 3.

When the resin component 15 is a thermosetting resin component, for example, the above-described dividing step (Fig. 2(b)), the laminating step (Fig. 2(c)), and the hot pressing step (Fig. 2) are repeatedly performed in an uncured state. A series of steps of 2(a)) directly obtains the thermally conductive sheet 3 in an uncured state. Further, after the thermally conductive sheet 3 in an uncured state is attached to the image pickup unit 1, it is thermally cured as necessary.

Further, in the thermally conductive sheet 3 thus formed, as shown in FIG. 3 and a partial enlarged pattern thereof, the longitudinal direction LD of the boron nitride particles 14 is along the intersection (orthogonal) to the thickness of the thermally conductive sheet 3. The orientation of the direction of the TD is SD alignment.

The arithmetic mean of the angle between the longitudinal direction LD of the boron nitride particles 14 and the surface direction SD of the thermally conductive sheet 3 (the alignment angle α of the boron nitride particles 14 with respect to the thermally conductive sheet 3) is, for example, 25 Below the degree, it is preferably 20 degrees or less, and usually 0 degree or more.

Further, the alignment angle α of the boron nitride particles 14 with respect to the thermally conductive sheet 3 is calculated by cutting the thermally conductive sheet 3 by a cross-section polisher (CP) in the thickness direction so as to be able to observe The cross-sectional magnification of 200 or more boron nitride particles 14 was taken by a scanning electron microscope (SEM) to obtain a cross section, and the long-side direction LD of the boron nitride particles 14 was obtained from the obtained SEM photograph. The inclination angle of the surface direction SD of the thermally conductive sheet 3 (the direction orthogonal to the thickness direction TD) was calculated and the average value was calculated.

Thereby, the thermal conductivity of the surface direction SD of the thermally conductive sheet 3 is 4 W/m‧K or more, preferably 5 W/m‧K or more, more preferably 10 W/m‧K or more, and further preferably 15 W/m‧K or more, especially preferably 25 W/m‧K or more, usually less than 200 W/m‧K.

In addition, when the thermal conductivity of the surface direction SD of the thermally conductive sheet 3 is a thermosetting resin component, the resin component 15 is substantially the same before and after thermosetting.

When the thermal conductivity of the surface direction SD of the thermally conductive sheet 3 is less than the above range, the thermal conductivity in the plane direction SD is insufficient, and thus it may not be used for the heat release application requiring the thermal conductivity of the surface direction SD.

Further, the thermal conductivity of the surface direction SD of the thermally conductive sheet 3 was measured by a pulse heating method. In the pulse heating method, a xenon flash thermal conductivity analyzer "LFA-447 type" (manufactured by NETZSCH Co., Ltd.) was used.

Further, the thermal conductivity of the thermally conductive sheet 3 in the thickness direction TD is, for example, 0.5 to 15 W/m‧K, preferably 1 to 10 W/m‧K.

Further, the thermal conductivity of the thermally conductive sheet 3 in the thickness direction TD is measured by a pulse heating method, a laser flash method, or a TWA (Temperature Wave Analysis) method. In the pulse heating method, the same as the above is used, and "TC-9000" (manufactured by ULVAC Corporation) is used in the laser flash method, and "ai-Phase mobile" (manufactured by ai-Phase Co., Ltd.) is used in the TWA method.

Thereby, the ratio of the thermal conductivity of the surface direction SD of the thermally conductive sheet 3 to the thermal conductivity of the thickness direction TD of the thermally conductive sheet 3 (thermal conductivity in the plane direction SD / thermal conductivity in the thickness direction TD) is, for example, 1.5 or more. It is preferably 3 or more, more preferably 4 or more, and usually 20 or less.

Further, although not shown in FIG. 2, a void (gap) is formed in the thermally conductive sheet 3, for example.

The ratio of the voids in the thermally conductive sheet 3, that is, the void ratio P, can be made by the ratio of the boron nitride particles 14 (volume basis), and further by the hot pressing of a mixture of the boron nitride particles 14 and the resin component 15 ( Adjusting the temperature, pressure and/or time of Fig. 2(a)), specifically, by setting the temperature, pressure and/or time of the hot pressing (Fig. 2(a)) within the above range Make adjustments.

The porosity P in the thermally conductive sheet 3 is, for example, 30% by volume or less, preferably 10% by volume or less.

The void ratio P is measured, for example, by first cutting the thermally conductive sheet 3 in the thickness direction by a cross-section polisher (CP), and observing it by a scanning electron microscope (SEM) at 200 times. In the cross section, an image is obtained, and from the obtained image, the void portion and the other portions are binarized, and then, the area ratio of the void portion to the entire cross-sectional area of the thermally conductive sheet 3 is calculated.

Further, in the thermally conductive sheet 3, the void ratio P2 after curing is, for example, 100% or less, preferably 50% or less, with respect to the void ratio P1 before curing.

In the measurement of the porosity P (P1), when the resin component 15 is a thermosetting resin component, the thermally conductive sheet 3 before thermal curing is used.

When the porosity P of the thermally conductive sheet 3 is within the above range, the step followability (described later) of the thermally conductive sheet 3 can be improved.

Further, in the bending resistance test of the cylindrical conductive mandrel according to the cylindrical mandrel method according to JIS K 5600-5-1, it is preferable that no fracture is observed when the thermal conductive sheet 3 is evaluated under the following test conditions.

Test conditions

Test device: Type I

Mandrel: 10 mm in diameter

Bending angle: 90 degrees or more

Thickness of the thermally conductive sheet 3: 0.3 mm

Further, a three-dimensional diagram of the I-type test apparatus is shown in Figs. 5 and 6, and a type I test apparatus will be described below.

In FIG. 5 and FIG. 6, the I-type test apparatus 90 includes a first flat plate 91 and a second flat plate 92 arranged in parallel with the first flat plate 91, and is provided to rotate the first flat plate 91 and the second flat plate 92 relatively. Mandrel (rotation axis) 93.

The first flat plate 91 is formed substantially in a rectangular flat plate shape. Further, a stopper portion 94 is provided at one end portion (movable end portion) of the first flat plate 91. The stopper portion 94 is formed on the surface of the second flat plate 92 so as to extend along one end portion of the second flat plate 92.

The second flat plate 92 is formed in a substantially rectangular flat shape, and one side of the first flat plate 92 and one side of the first flat plate 91 (one end portion (base end portion) on the side opposite to the end portion on which one end of the stopper portion 94 is provided) ) Adjacent connection configuration.

The mandrel 93 is formed to extend along one side of the adjacent first flat plate 91 and second flat plate 92.

As shown in Fig. 5, the type I test apparatus 90 has the surface of the first flat plate 91 and the surface of the second flat plate 92 as one plane before the start of the bending resistance test.

Further, in order to carry out the bending resistance test, the thermally conductive sheet 3 is placed on the surface of the first flat plate 91 and the surface of the second flat plate 92. Further, the thermally conductive sheet 3 is placed such that one side thereof abuts against the stopper portion 94.

Next, as shown in FIG. 6, the first flat plate 91 and the second flat plate 92 are relatively rotated. Specifically, the movable end portion of the first flat plate 91 and the movable end portion of the second flat plate 92 are rotated at a specific angle around the mandrel 93. Specifically, the first flat plate 91 and the second flat plate 92 are rotated such that the surfaces of the movable end portions thereof approach (opposite).

Thereby, the thermally conductive sheet 3 is bent around the mandrel 93 while following the rotation of the first flat plate 91 and the second flat plate 92.

Further, it is preferable that the thermally conductive sheet 3 has no fracture observed even when the bending angle is set to 180 degrees under the above test conditions.

In the case where the resin component 15 is a thermosetting resin component, the thermally conductive sheet 3 for the bendability test is a semi-cured (B-stage state) thermally conductive sheet 3.

In the bending resistance test of the above-described bending angle, when the thermally conductive sheet 3 is observed to be broken, the thermal conductive sheet 3 may not be provided with excellent flexibility.

Further, in the three-point bending test according to JIS K 7171 (2008), the heat conductive sheet 3 was evaluated under the following test conditions, and for example, no fracture was observed.

Test conditions

Test piece: size 20 mm × 15 mm

Distance between fulcrums: 5 mm

Test speed: 20 mm/min (pressure speed under the pressure)

Bending angle: 120 degrees

Evaluation method: The crack in the central portion of the test piece at the time of the test under the above test conditions was observed by visual observation.

In the case where the resin component 3 is a thermosetting resin component in the three-point bending test, the thermally conductive sheet 3 before thermal curing is used.

Therefore, the thermally conductive sheet 3 was not observed to have been broken in the above three-point bending test, and therefore the step followability was excellent. In addition, the step followability refers to the fact that when the thermally conductive sheet 3 is placed on a setting object having a step difference, the characteristics are closely followed along the step.

Further, for example, a mark such as a character or a mark may be attached to the thermally conductive sheet 3. That is, the heat conductive sheet 3 is excellent in the label adhesion property. The label adhesion refers to a property of reliably adhering the above-mentioned label to the thermally conductive sheet 3.

Specifically, the mark can be attached (coated, fixed or fixed) to the thermally conductive sheet 3 by printing or imprinting or the like.

Examples of the printing include inkjet printing, letterpress printing, gravure printing, and laser printing.

Further, when printing a mark by inkjet printing, letterpress printing or gravure printing, for example, an ink fixing layer for improving the fixing property of the marking can be provided on the surface of the heat conductive sheet 3 (printing side surface) ).

Further, in the case of printing a mark by laser printing, for example, a toner fixing layer for improving the fixing property of the mark can be provided on the surface (printing side surface) of the heat conductive sheet 3.

As the imprinting, for example, laser marking, engraving, and the like can be cited.

Further, the thermally conductive sheet 3 thus obtained is usually insulative.

Further, when such an image pickup element 1 is obtained, it is not particularly limited. For example, the image pickup element 2 is first produced, and then the heat conductive sheet 3 is bonded to the back surface of the obtained image pickup element 2.

The method of manufacturing the image pickup element 2 is not particularly limited, and a known method can be employed.

More specifically, although not shown, the light-receiving element 10 is buried in the light-receiving substrate 7 by a known method, and the insulating layer 8 and the conductor pattern 9 are sequentially laminated, thereby forming the circuit substrate 6 on the light-receiving substrate 7. . Thereafter, the filter 5 and the collecting lens 4 are placed on the circuit board 6. Thereby, the image pickup element 2 can be obtained.

Next, in this method, the thermally conductive sheet 3 is bonded to the back surface of the obtained image pickup element 2.

In the case where the resin component 15 is a thermosetting resin component in the thermally conductive sheet 3, it is preferable to bond the thermally conductive sheet 3 in the B-stage state to the back surface of the image sensor 2. Thereby, the imaging unit 1 is obtained.

Further, although not shown, when the thermally conductive sheet 3 is in the B-stage state in the image pickup device 1, the image pickup member 1 can be heated as needed, and the thermally conductive sheet 3 can be thermally cured. Further, the timing and conditions of the thermal curing are appropriately determined depending on the purpose and use.

Further, although not shown, a diverging lens, a light guiding member, and the like may be appropriately disposed in the imaging component 1 as needed.

Further, such an image pickup unit 1 is mounted on an image pickup apparatus such as a digital camera or a digital camera.

Further, in the image pickup device, light incident from the light incident surface (light incident surface of the condensing lens 4) is collected by the condensing lens 4, and penetrates the filter 5 (green filter). 5G, red filter 5R or blue filter 5B) and the insulating layer 8 portion of the circuit substrate 6. Thereby, the light reaches the light receiving substrate 7 (light receiving element 10).

The light reaching the light-receiving substrate 7 is converted into an electrical signal by the light-receiving element 10, and the electric signal is transmitted by the conductor pattern 9 for use in an external member (not shown).

At this time, in the image pickup device 2, heat is generated in the circuit board 6 or the light-receiving substrate 7 or the like. However, when the image pickup device 2 is at a high temperature, problems such as noise generation may occur, and sensitivity may exist. A situation that changes depending on its temperature conditions.

On the other hand, in the imaging device 1 , the thermally conductive sheet 3 is provided on the back surface disposed on the opposite side of the light incident surface of the image sensor 2, and in detail, it includes plate-like boron nitride particles and is oriented in the thickness direction. The thermally conductive sheet 3 having a thermal conductivity of 4 W/m‧K or more in the direction orthogonal to the direction (that is, the direction in which the back surface of the light-receiving substrate 7 extends). Therefore, the heat generated from the back surface of the light-receiving substrate 7 can be uniformly diffused in the surface direction, the temperature unevenness can be reduced (the temperature is uniformized), and the excellent heat dissipation property can be ensured, and as a result, the sensitivity can be improved.

Further, since such a thermally conductive sheet 3 can be manufactured at a lower cost than the graphite sheet, cost reduction can be achieved.

Further, since the graphite sheet is electrically conductive, for example, there is a problem that if a defect occurs or the like, the chip is short-circuited inside the image pickup apparatus.

However, since such a thermally conductive sheet 3 is insulative, it is possible to prevent the occurrence of a short circuit even when a defect occurs inside the imaging device (not shown).

Fig. 4 is a schematic block diagram showing another embodiment of the image pickup unit 1 of the present invention.

It is to be noted that the same reference numerals are given to the components in the above-mentioned respective portions, and the detailed description thereof will be omitted.

In the above description, the image pickup device 2 is a surface illumination type CMOS image sensor in which the circuit board 6 is disposed under the condensing lens 4 and the filter 5, and the light receiving substrate 7 is disposed under the circuit board 6. As the image pickup element 2, for example, a known back side illumination type CMOS image sensor can be used.

More specifically, in this embodiment, as shown in FIG. 4, the light-receiving substrate 7 is disposed under the condensing lens 4 and the filter 5, and the circuit board 6 is placed under the light-receiving substrate 7.

In addition, at this time, the light-receiving substrate 7 is usually cut off by a polyoxymethylene resin or the like, and is reduced in thickness.

Further, in the image pickup device 1, the thermally conductive sheet 3 is bonded to the back surface of the circuit board 6 (the back surface of the image sensor 2).

In the same manner as described above, the image pickup unit 1 can ensure excellent heat dissipation, achieve uniform temperature, and achieve cost reduction.

Further, in the image pickup device 1, the image pickup device 2 is a back side illumination type CMOS image sensor, so that the efficiency of light reaching the light receiving substrate 7 (light receiving element 10) can be improved, and the sensitivity can be improved.

In other words, in the image pickup device 1 (see FIG. 1) in which the image pickup device 2 is a surface illumination type CMOS image sensor, light incident from the light incident surface penetrates the circuit substrate 6 before reaching the light receiving substrate 7 (light receiving element 10). Therefore, light is reflected by the conductor pattern 9 in the circuit board 6, and the efficiency of the light reaching the light-receiving board 7 (light-receiving element 10) cannot be sufficiently ensured.

However, in the imaging device 1 (see FIG. 4) in which the imaging element 2 is a back-illuminated CMOS image sensor, light incident from the light incident surface reaches the light receiving substrate 7 (light receiving element 10) before penetrating the circuit substrate 6. Therefore, it is possible to suppress the reflection of light by the conductor pattern 9 and the like, and to sufficiently ensure the efficiency of the light reaching the light-receiving substrate 7 (light-receiving element 10).

Example

The invention will be more specifically described below, but the invention is not limited by the examples.

Production Example 1 (Manufacture of Thermal Conductive Sheet)

PT-110 (trade name, plate-shaped boron nitride particles, average particle diameter (light scattering method) 45 μm, manufactured by Momentive Performance Materials Japan Co., Ltd.) 13.42 g, JER828 (trade name, bisphenol A epoxy resin, The first epoxy resin, liquid, epoxy equivalent 184 ~ 194 g / eqiv., softening temperature (global method) less than 25 ° C, melt viscosity (80 ° C) 70 mPa ‧ s, manufactured by Japan Epoxy resin company) 1.0 g, and EPPN-501HY (trade name, triphenylmethane epoxy resin, second epoxy resin, solid, epoxy equivalent 163 ~ 175 g / eqiv., softening temperature (ring and ball method) 57 ~ 63 ° C, Manufactured by Nippon Kasei Co., Ltd., 2.0 g, hardener (5 mass% methyl ethyl ketone dispersion of Curezol 2P4MHZ-PW (trade name, manufactured by Shikoku Chemicals Co., Ltd.)) 3 g (solid content 0.15 g) (relative to The total amount of JER828 and EPPN-501HY as epoxy resin was 5% by mass), and the mixture was stirred at room temperature (23 ° C) for 1 night to volatilize methyl ethyl ketone (the dispersion medium of the hardener). A semi-solid mixture was prepared.

Furthermore, in the above formulation, the volume fraction (% by volume) of the total volume of the boron nitride particles relative to the solid content of the hardener (ie, the solid content of the boron nitride particles and the epoxy resin) is 70 volumes. %.

Next, the obtained mixture was sandwiched by two release films treated with polyoxyxylene, and a vacuum heat press was used at a temperature of 80 ° C and 10 Pa (vacuum environment) at a load of 5 tons (20 MPa). These hot pressing was carried out for 2 minutes to obtain a pressed sheet having a thickness of 0.3 mm (refer to Fig. 2 (a)).

Thereafter, the obtained pressed sheet is cut into a plurality of pieces when projected in the thickness direction of the pressed sheet, thereby obtaining a divided sheet (see FIG. 2(b)), and then the divided sheet is then A laminated sheet is obtained by laminating in the thickness direction (see Fig. 2(c)).

Next, the obtained laminated sheet was hot-pressed by the same vacuum heat press as described above under the same conditions as above (see Fig. 2(a)).

Next, one of the above-described cutting, laminating, and hot pressing operations (see FIG. 2) was repeated four times to obtain a thermally conductive sheet having a thickness of 0.3 mm (unhardened state) (see FIG. 3).

Manufacturing Examples 2~9 and 11~16

According to the formulation and manufacturing conditions of Tables 1 to 3, the same treatment as in Production Example 1 was carried out to obtain a thermally conductive sheet.

Manufacturing Example 10

According to the formulation of Table 2, the components (boron nitride particles and polyethylene) were blended and stirred, thereby preparing a mixture. That is, the mixture was heated to 130 ° C during the stirring of each component to melt the polyethylene.

Next, the obtained mixture was sandwiched by two release films treated with polyoxymethylene, and subjected to a vacuum heat press at a temperature of 120 ° C and 10 Pa (vacuum atmosphere) at a load of 1 ton (4 MPa). These hot pressing were carried out for 2 minutes, whereby a pressed sheet having a thickness of 0.3 mm was obtained (refer to Fig. 2 (a)).

Thereafter, the obtained pressed sheet is cut into a plurality of pieces when projected in the thickness direction of the pressed sheet, thereby obtaining a divided sheet (see FIG. 2(b)), and then the divided sheet is then A laminated sheet is obtained by laminating in the thickness direction (see Fig. 2(c)).

Next, the obtained laminated sheet was hot-pressed by the same vacuum heat press as described above under the same conditions as above (see Fig. 2(a)).

Next, a series of operations of cutting, laminating, and hot pressing were repeated four times (see Fig. 2) to obtain a thermally conductive sheet having a thickness of 0.3 mm (unhardened state).

Example 1

The thermally conductive sheet in the uncured (B-stage) state obtained in Production Example 1 was bonded to the back surface of the surface-illuminated image sensor disposed on the opposite side of the light incident surface (see FIG. 1). Thereafter, the film was heated at 150 ° C for 120 minutes to thermally cure the thermally conductive sheet to produce an image pickup member.

Example 2~16

The image-sensitive components of Examples 2 to 16 were produced in the same manner as in Example 1 using the thermally conductive sheets obtained in Production Examples 2 to 16.

Further, the thermally conductive sheet obtained in Production Example 10 was thermally fused at 120 ° C instead of thermal curing.

Example 17

The thermally conductive sheet in the uncured (B-stage) state obtained in Production Example 1 was bonded to the back surface of the back-illuminated image sensor disposed on the opposite side of the light incident surface (see FIG. 1). Thereafter, the film was heated at 150 ° C for 120 minutes to thermally cure the thermally conductive sheet to produce an image pickup member.

Example 18~32

The image pickup parts of Examples 18 to 32 were produced in the same manner as in Example 17 using the heat conductive sheets obtained in Production Examples 2 to 16.

Further, the thermally conductive sheet obtained in Production Example 10 was thermally fused at 120 ° C instead of thermal curing.

Comparative example 1

The surface illumination type image sensor used in Example 1 was used as an image pickup part. Further, a thermally conductive sheet is bonded to the image pickup member.

Comparative example 2

The back side illumination type image sensor used in Example 17 was used as an image pickup part. Further, the thermally conductive sheet is not attached to the image pickup member.

(Evaluation)

Thermal conductivity

The thermal conductivity of the thermally conductive sheets of Production Examples 1 to 16 was measured.

In other words, the thermal conductivity in the plane direction (SD) was measured by a pulse heating method using a xenon flash thermal conductivity analyzer "LFA-447 type" (manufactured by NETZSCH Co., Ltd.).

The results are shown in Tables 1 to 3.

2. Exothermic and temperature uneven

After the imaging members of Examples 1 to 32 were operated, the temperature of the thermally conductive sheet was measured by an infrared camera, and as a result, it was confirmed that there was almost no temperature rise and temperature unevenness.

In the same manner as described above, the imaging members of Comparative Examples 1 and 2 were operated, and the temperature of the back surface was measured by an infrared camera. As a result, temperature rise and temperature unevenness were confirmed.

3. Void ratio (P)

The void ratio (P1) of the thermally conductive sheet before heat curing of Production Examples 1 to 16 was measured by the following measurement method.

Method for measuring void ratio: First, the thermally conductive sheet was cut in the thickness direction by a cross-section polisher (CP), and the cross-section thus observed was observed by a scanning electron microscope (SEM) at 200 times to obtain a map. image. Thereafter, from the obtained image, the void portion and the other portions were subjected to binarization processing, and secondly, the area ratio of the void portion to the entire cross-sectional area of the thermally conductive sheet was calculated.

The results are shown in Tables 1 to 3.

4. Step followability (three-point bending test)

With respect to the heat conductive sheets before the heat curing of Production Examples 1 to 16, a three-point bending test under the following test conditions was carried out in accordance with JIS K 7171 (2010), and the step followability was evaluated based on the following evaluation criteria. The results are shown in Tables 1 to 3.

Test conditions

Test piece: size 20 mm × 15 mm

Distance between fulcrums: 5 mm

Test speed: 20 mm/min (pressure speed under the pressure)

Bending angle: 120 degrees

(evaluation benchmark)

◎: No cracking was observed at all.

○: Little cracking was observed.

×: Cracking was clearly observed.

5. Print mark visibility (print mark adhesion: mark adhesion of inkjet printing or laser printing)

The marks were printed on the thermally conductive layers of Production Examples 1 to 16 by inkjet printing and laser printing, and the marks were observed.

As a result, in the heat conductive layers of Production Examples 1 to 16, the marks printed by both the ink jet printing and the laser printing were well recognized, and the adhesion of the printed marks was confirmed to be good.

[Table 1]

[Table 2]

[table 3]

The numerical values in the respective components in Tables 1 to 3 indicate the number of g unless otherwise specified.

Further, in the column of boron nitride particles in Tables 1 to 3, the value of the upper stage is the blending mass (g) of the boron nitride particles, and the value of the middle stage is the boron nitride particle in the heat conductive sheet relative to the hardener. The volume fraction (% by volume) of the total volume of the solid component (ie, the solid content of the boron nitride particles and the epoxy resin or polyethylene), and the value of the lower segment indicates that the boron nitride particles are relative to the thermally conductive sheet. The volume fraction (% by volume) of the total volume of the solid component (i.e., the solid content of the boron nitride particles and the epoxy resin and the hardener).

In addition, the components of the symbols * in the respective components of Tables 1 to 3 are described below in detail.

PT-110 ^*1 : Product name, plate-shaped boron nitride particles, average particle size (light scattering method) 45 μm, manufactured by Momentive Performance Materials Japan

UHP-1 ^*2 : Product name: SHOBN UHP-1, plate-shaped boron nitride particles, average particle size, (light scattering method) 9 μm, manufactured by Showa Denko

Epoxy Resin A ^*3 : OGSOL EG (trade name), bisaryl fluorene epoxy resin, semi-solid, epoxy equivalent 294 g/eqiv., softening temperature (ring and ball method) 47 ° C, melt viscosity (80 ° C )1360 mPa‧s, manufactured by Osaka Gas Chemical Co., Ltd.

Epoxy resin B ^*4 : JER828 (trade name), bisphenol A epoxy resin, liquid, epoxy equivalent 184~194 g/eqiv., softening temperature (ring and ball method) less than 25 ° C, melt viscosity (80 °C) 70 mPa‧s, manufactured by Japan Epoxy Resin Co., Ltd.

Epoxy resin C ^※5 : JER1002 (trade name), bisphenol A epoxy resin, solid, epoxy equivalent 600~700 g/eqiv., softening temperature (ring and ball method) 78°C, melt viscosity (80°C) 10000 mPa ‧ or more (above the measurement limit), manufactured by Japan Epoxy Resin Co., Ltd.

Epoxy resin D ^*6 : EPPN-501HY (trade name), triphenylmethane epoxy resin, solid, epoxy equivalent 163~175 g/eqiv., softening temperature (ring and ball method) 57~63°C, Japan Chemical company manufacturing

Hardener ^*7 : 5 mass% methyl ethyl ketone solution of Curezol 2PZ (trade name, manufactured by Shikoku Chemicals Co., Ltd.)

Hardener ^*8 : 5 mass% methyl ethyl ketone dispersion of Curezol 2P4MHZ-PW (trade name, manufactured by Shikoku Chemicals Co., Ltd.)

Polyethylene ^*9 : low-density polyethylene, weight average molecular weight (Mw) 4000, number average molecular weight (Mw) 1700, manufactured by Aldrich Co., Ltd., the above description is provided by way of an exemplified embodiment of the present invention, but only As an example, it is not to be construed as limiting. Modifications of the invention that are apparent to those skilled in the art are included in the scope of the appended claims.

1. . . Camera parts

2. . . Camera element

3. . . Thermally conductive sheet

3A. . . Pressed sheet

3B. . . Split sheet

3C. . . Laminated sheet

4. . . Condenser lens

5. . . Filter

5B. . . Blue filter

5G. . . Green filter

5R. . . Red filter

6. . . Circuit substrate

7. . . Light receiving substrate

8. . . Insulation

9. . . Conductor pattern

10. . . Light receiving element

14. . . Boron nitride particles

15. . . Resin composition

16. . . Release film

90. . . Type I test device

91. . . First tablet

92. . . 2nd tablet

93. . . Mandrel (rotary axis)

94. . . Stop

LD. . . Long side direction

TD. . . Thickness direction

SD. . . Face direction

α. . . Orientation angle

1 is a schematic configuration diagram of an embodiment of an image pickup component of the present invention;

FIG. 2 is a view showing a step of explaining a method of manufacturing the thermally conductive sheet provided in the image pickup unit shown in FIG. 1;

Figure 2 (a) shows the step of hot pressing the mixture or the laminated sheet;

Figure 2 (b) shows the steps of dividing the pressed sheet into a plurality of pieces;

Figure 2 (c) shows the step of layering the divided sheets;

Figure 3 is a perspective view of the heat conduction sheet shown in Figure 2;

Fig. 4 is a view showing a schematic configuration of another embodiment of the image pickup unit of the present invention;

Figure 5 is a perspective view showing a type I test device (before the bending resistance test) of the bending resistance test;

Fig. 6 is a perspective view showing a type I test apparatus (in the middle of the bending resistance test) of the bending resistance test.

1. . . Camera parts

2. . . Camera element

3. . . Thermally conductive sheet

4. . . Condenser lens

5. . . Filter

5B. . . Blue filter

5G. . . Green filter

5R. . . Red filter

6. . . Circuit substrate

7. . . Light receiving substrate

8. . . Insulation

9. . . Conductor pattern

10. . . Light receiving element

Claims (7)

An image pickup device comprising: an image pickup element including a light incident surface on which light is incident and a back surface disposed on a side opposite to the light incident surface; and a thermally conductive sheet provided on the back surface to be imaged from the image pickup unit The heat-conductive sheet contains plate-shaped boron nitride particles, and the thermal conductive sheet has a thermal conductivity of 4 W/m·K or more in a direction orthogonal to the thickness direction, and the thermally conductive sheet is used. The void ratio is 30% by volume or less. The imaging component of claim 1, wherein the imaging component is a CMOS image sensor. The imaging component of claim 1, wherein the imaging element is a back-illuminated CMOS image sensor. The image pickup unit of claim 1, wherein the void ratio is 10% by volume or less. The image pickup unit of claim 1, wherein the boron nitride particles are dispersed in the resin component. The image-capturing part of claim 1, wherein the thermally conductive sheet is prepared by hot-pressing a mixture prepared by mixing the boron nitride particles and a resin component to prepare a pressed sheet, and a dividing step, which will The pressed sheet is divided into a plurality of divided sheets, and a laminating step of laminating the plurality of divided sheets to prepare a laminated sheet, and A hot pressing step of hot pressing the laminated sheet. The image-capturing part of claim 6 is subjected to the step of performing the above-described dividing step, the laminating step and the hot pressing step, thereby preparing the thermally conductive sheet, and the number of repetitions of the steps is 2 to 7 times.